In a conventional wireless communication system, a communication environment may deteriorate because a signal of another system becomes an interference signal for a desired signal.
For example, in broadcasting satellite reception equipment having a BS (broadcasting satellite) antenna installed in each house, frequency conversion is often used to process a received signal. If radio waves leak from the reception equipment at that time, a band of a cell phone is interfered.
A signal band as an interference signal for a band of a cell phone as a desired signal is wider than the band of the cell phone, it is difficult to remove the interference signal by a filter or the like. A known interference signal can be removed by generating a replica as a reference. However, when it is not possible to prepare a replica of the interference signal, it is difficult to remove only the interference signal.
As for a related prior art, there is Japanese Patent Application Publication No. 2009-272767 “interference wave canceler relay device” (Hitachi Kokusai Electric Inc.) (Patent Document 1).
In Patent Document 1, the interference wave canceler relay device allows a filter factor of a complex FIR filter unit required for a diffracted wave canceler to be updated accurately.
Patent Document 1: Japanese Patent Application Publication No. 2009-272767
However, in the conventional wireless communication system for a cell phone, the interference signal from another system such as the broadcasting satellite reception equipment having a BS antenna may not be removed, which results in deterioration of a communication quality of a cell phone as a desired signal.
In Patent Document 1, the diffracted wave is canceled and, thus, the interference signal from another system is not removed.